June 29, 1905J 



NATURE 





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ROWLAND WARD, 



Naturalists and Manufacturers of '' 



ENTOMOLOGICAL APPARATUS 

 AND CABINETS. 



MAMMAL SKINS. BIRD SKINS. 

 BIRDS" EGGS inclutcheswith full data. 



BOOKS ON ALL NATURAL HISTORY SUBJECTS. 

 Catalogues Post Free. 



THE JUNGLE, 166 PIGCACILLY, LONDON. 



LABORATORIES FURNISHED 



Chemical, Physical, and all Science Laboratories 



completely equip]ied with Benches, Fume 



Chambers, Cupboards, lVc, and Scientific 



Apparatus of every description. 



SE\D SPECIFICATIOX l^OIt OUR J'RICX.S. 



We also supply Sinks, Gas and Water Fittings 

 specially designed for Science Laboratories. 



A. GALLENKAMP & CO., Uh 



19 & 21 Sun Street, Finsbury Square, LONDON. E.C. 



RADIUM 



We have a limited consigrnment of 



RADIUM BROMIDE 



of the 

 VERY HIGHEST ACTIVITY, 



and are open to supply same in 



5 mgf. tubes at a 



REASONABLE PRICE. 



Manufacturing Chemist, 



10 NEW CAVENDISH STREET, LONDON, W. 



Telephone : lyg; Paddinqton 



Telegrams ; Martindale, Chemist, London, 



DIFFRACTION GRATINGS 



3 l3y 3 cxYis. 1^^ - GStclx, 



Prof. H. A. ROlfiriiAND'S GRATINGS, 



14,438 lines to tlie inch. 



PLANE AND CONCAVE, from JS7 XOs. 



PETER HEELE, 



Maker of Astronomical Instruments, 

 115 HIGH HOLBORN, LONDON, W.C. 



GRAND PRIX 



I Paris, 1900. 



I St. Louis, 1904. 



And other High Awards. 



Ti'Ufjfaphic Address: "ARCTITVDE, LOXDOX." 



